FELINE IMMUNODEFICIENCY VIRUS
By: Neva DeCoux, Michelle Kwok
ETIOLOGY
Feline immunodeficiency virus (FIV) is a type of
lentivirus ("slow virus") classified by a long incubation
period (may last as long as 6 years) that slowly
develops into the disease.
It is in the same retrovirus family as feline leukemia
virus (FeLV) and human immunodeficiency virus (HIV).
It attacks the immune system, and as a result, the cat is
unable to fight off various infections and cancers.
Approximately 2.5% of cats in the United States are
infected with FIV.
CAUSE
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The virus, a lentivirus, interacts with
lymphocytes, changing their ability to function
normally in the immune response process.
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The resulting lymphopenia, loss of memory cell
function, and decrease in antibody production
from T-cell stimulated lymphocytes leaves the
cat open for opportunistic infection.
RETROVIRUSES
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Retroviruses are species-specific. This means a feline retrovirus
like FIV will only infect cats; a human retrovirus such as HIV will
only infect humans.
Retroviruses are made up of RNA. In the host, the RNA is
transcribed into DNA and incorporated into the DNA of the
host’s cells.
Retroviruses are fragile, being easily inactivated by ultraviolet
light, heat, detergents, and drying.
HISTORY OF DISEASE
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It was first discovered during the investigation of a
disease outbreak in a previously healthy colony of
rescue cats at UC Davis in 1986 by immunologists
Janet Yamamoto and Niels Pederson
The colony had been showing similar signs to people
with acquired immunodeficiency syndrome (AIDS)
caused by human immunodeficiency virus (HIV)
infection.
Yamamoto started working on a vaccine for FIV at UC
Davis.
SIGNALMENT
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Vulnerable at any age
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Outdoor, free-roaming felines
are at greater risk
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Male felines are 1.5 to 3 times more likely to become infected
then a female feline.
Is rare in catteries
More predominant in free-roaming aggressive male
cats due to transmission by bite wounds
Infects domestic cats, and can also infect wild felines
including snow leopards, lions, tigers, jaguars, Florida
panthers, and bobcats.
ROAMING MALE FELINE
FELINE WITH FIV
- Feline Male was diagnosed to be
FIV positive.
TRANSMISSION
The primary modes of FIV transmission
are deep bite wounds and scratches,
where the infected cat's saliva enters the
other cat's bloodstream.
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Casual, non-aggressive contact does not appear to be an efficient route of
spreading FIV.
On rare occasions infection is transmitted from an infected mother cat to
her kittens, usually during passage through the birth canal or when the
newborn kittens ingest infected milk
FIV transmission in utero or through the mother's milk is very rare. It could
possibly occur if the queen is infected during pregnancy or while nursing
the kittens.
Queens infected with FIV prior to the pregnancy usually have non-infected
kittens.
TRANSMISSION
Sexual contact is not a major means of
spreading FIV.
 Although FIV is a lentivirus similar to HIV (the
human immunodeficiency virus) and causes a
disease in cats similar to AIDS (acquired
immune deficiency syndrome) in humans, it is a
highly species-specific virus that infects only
felines.
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CLINICAL SIGNS
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Poor coat condition and persistent fever with a loss of appetite
are commonly seen.
Lethargy
Inflammation of the gums (gingivitis) and mouth (stomatitis)
and chronic or recurrent infections of the skin, urinary bladder,
and upper respiratory tract are often present.
Persistent diarrhea
Slow but progressive weight loss is common, followed by severe
wasting late in the disease process.
Various kinds of cancer and blood diseases are much more
common in cats infected with FIV, too.
In unspayed female cats, abortion of kittens or other
reproductive failures have been noted.
Some infected cats experience seizures, behavior changes, and
other neurological disorders.
CLINICAL SIGNS
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Febrile episodes
Lymphadenopathy (chronically swollen lymph nodes)
Persistent infections unresponsive to treatment
Weight loss
Pansystemic disease
Gingivitis
Ocular lesions
Slow-healing traumatic wounds
Behavior abnormalities
Chronic upper respiratory infections
Anemia
DIAGNOSTIC TESTS AND EXPECTED RESULTS
Immunoblotting
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Uses anti-bodies to detect
HIV related proteins
PCR (polymerase chain
reaction)
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Elisa (Enzyme-linked
immunosorbent assay)
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Detects anti-FIV antibodies
Most common
Rapid and reliable method
Does not work well with very early
infection
False positive is very rare
Repeat test to be sure
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Detects the virus itself
Very useful for detecting
infection in kittens born from
the FIV positive mother
Check for false positives
DIAGNOSTIC TESTS
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ELISA test (enzyme-linked immunosorbent assay): will be positive
-It is possible to get false positive or false negatives from these results for the
following reasons:
False Positive
False Negative
•Kittens born to FIV infected mothers may
have received antibodies from their mother’s
milk. This doesn’t mean that the kitten has
FIV, just that it has received antibodies to FIV.
Kittens that test positive should be re-tested
at a later date.
•It usually takes several weeks for the
antibodies for FIV to appear in the blood, if a
cat is tested prior to this it will show a
negative test result.
•If a cat has received the FIV vaccine the test
results will show up positive.
•If the cat is in the later sages of infection it
may not be producing antibodies.
ELISA TEST  PCR TEST
DIAGNOSTIC TEST CONT.
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A FIV PCR (polymerase chain reaction) test is available in some commercial
laboratories. PCR detects the presence of the FIV virus in the blood.
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Western blot test or IFA (Immuno-Fluorescent Antibody Test): If a cat has
tested positive to FIV it is sometimes recommended to follow up with either
a Western Blot Test or an IFA test.
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If your cat has tested positive to FIV but you are not sure if it has had the
vaccine, or want to be sure it does/doesn't have the virus then you may be
able to request a PCR (polymerase chain reaction) test, which will be able to
detect the presence of FIV DNA in the blood.
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Urinalysis: elevated protein levels
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CBC (stage 3): anemia, lymphopenia, neutropenia
WESTERN BLOT
TEST
RECOMMENDED TREATMENT
No treatment to eliminate the virus
 Depends on the proper health management
 There are some anti-viral medications but they
are not 100% effective in improving the
immune system
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TREATMENTS
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FIV is treated symptomatically.
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Medications:
-Antibiotics for secondary infections
-Appetite stimulants
-Corticosteroids
-Immune modulators
Dental extractions with chronic gingivitis and stomatitis
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Some also require nutritional support, fluid
therapy, and dental care.
PROGNOSIS
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It is not possible to determine how long a FIV
positive feline will live, but with proper care and
supportive therapy they can live a full life.
PROGNOSIS
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The outlook for cats that show severe, chronic, multiple signs of
disease is poor.
If clinical signs have developed only recently and are not severe,
there is a reasonable prospect of improvement with treatment,
which may be maintained for some time.
Greater than 50% of infected felines remain asymptomatic within 2
years after diagnosis
Treatment usually consists of supportive therapy, often antibiotics,
possibly coupled with antiviral therapy.
Felines in the terminal stage of the disease survive less then one
year.
For kittens can detect maternal AB hence re-test after 6 months.
Average life span from diagnosis to death is roughly around 5 years.
PATHOLOGIC LESIONS
University of Bristol School of Veterinary Science Study
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A range of tissues from a total of 17 cats naturally infected with the feline
immunodeficiency virus was examined histologically.
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In 11 cases, chronic inflammatory lesions were present in various tissues
including, most commonly, the intestine, brain and lung. Extensive
inflammation in the intestinal wall was present in seven of the cats.
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No particular bacterial organisms were demonstrated in these
inflammatory lesions. A range of changes was present in the lymph nodes,
including hyperplasia, atrophy or a mixed pattern. Erythrophagocytosis was a
consistent feature.
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Some present with dysplastic nodes characterized by follicular atrophy
(wasting away of the follicles), paracortical cell depletion, and fibrosis
(excess fibrous connective tissue).
PATHOLOGIC LESIONS OF DISEASE
The most commonly occurring lesions (seen in
91% of infected cats) were thymic atrophy,
generalized lymphoid hyperplasia, and bone
marrow hyperplasia.
 The second most common lesions were splenic
lymphoid hyperplasia and thymic follicle
formation (78–83% of cats).
 A third set of miscellaneous lymphoid and
mucosal lesions was confined to ≤30% of cats.
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PREVENTION
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Isolate affected cats.
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Keep unaffected cats away from feral cats.
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A vaccine for FIV currently is available
- may test positive for FIV at a later date
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Spaying and neutering outdoor cats can limit
exposure by decreasing aggressive behaviors.
- especially males
FIV VACCINE
Pros
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Provides 82% protection
against strain A.
Cons
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No blood test can differentiate
between a vaccinated cat and
a truly infected FIV positive cat.
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Does not provide full protection
against all strains.
Since it is a killed virus,
adjuvants are used which carry
the possibility of vaccine
associated sarcomas forming.
Vaccinated feline will always be
FIV positive. Can be a problem if
lost and placed in a shelter.
CLIENT EDUCATION
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Educate about the virus and vaccine
FIV is a progressive disease
FIV infected felines should be confined indoors to prevent the
spread of the virus
FIV infected felines should be spayed or neutered
Should be fed complete and balanced nutritional diet
Uncooked food should not be fed (Ex: raw meat, eggs and
unpasteurized dairy products)
Wellness visits for FIV infected felines should be scheduled with
your veterinarian at least every six months
Close monitoring of health and behavior
Test all new additions to the cat’s household.
REFERENCES
http://www.vet.cornell.edu/fhc/brochures/fiv.html
http://www.knowyourcat.info/health/fiv.html
http://www.fivprognosis.org/owners.html
http://www.peteducation.com/article.cfm?c=1+1316&aid=213
REFERENCES
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Common Diseases of Companion Animals
Veterinary Technician’s Daily Reference Guide
www.vet.cornell.edu
www.merckvetmanual.com
www.cat-world.com.au
http://gateway.nlm.nih.gov
http://fabcates.org
http://sciencedirect.com